John Deere 2020 hydraulic issues

[Lanefird]

First off thanks for adding me to the forum, Ive read many posts and learned a lot on here.
I recently bought a 1966 John Deere 2020. Ran fine, had some bad shutter in the hydraulic system. Got it home changed the hydraulic fluid, filters, cleaned all the screens, nothing too bad on them. Shutter seemed better.

Then after a week or so of using it to move some dirt all my hydraulics got real slow and then stopped all together. I had a leak in one of the rockshaft valves, oil was moving around in the rockshaft area, fixed that, no leak now. My loader was plumbed into the rear SCV quick connects, supply and return. Sooo,
I have replumbed the loader with a tee into the pressure line by the brake pedals, put the return line into a ported hydraulic filter cover. Replaced the old loader control valve with a new one and installed the closed center conversion plug and closed the pressure valve all the way down on it.
After installing the new loader valve and after the replumbing, everything worked amazing for about 30 minutes, no shutters, plenty of power, etc. Then after about 30 minutes it started to shutter again, and now its slow and some times wont move at all again.
I double checked the return line from the loader, now fluid coming out when running and in neutral position, no fluid moving inside rockshaft area.
Help!

 

[rScotty]

Hmm.... if it is happening after 30 minutes of use but works OK until then it is likely to be either either you missed a clogged filter, or some restriction is causing the fluid to heat up. Is the fluid getting really hot? That would be a clue.

I wish I knew more about the JD closed center type hydraulic system....but I don't. I do know that that closed hydraulic systems for medium size ag tractors tend to be unique to JDs and require some study. It's a field of its own. Luckily there are a lot of really good shop manuals and resources from that era.

Also, if you simply google "John Deere 2020 shudder" you will find that shuddering is a common problem. Lots has been written, and some of it by people who still post on tractor forums.
By the way, the keyword to use for that google search is "shudder"; NOT "shutter".
rScotty

 

[Tx Jim]

Welcome to TBN
You need to check trans pump GPM flow. If you don't have a JD 2020 tech manual I'll suggest you acquire one & study it.

 

[Lanefird]

Hmm.... if it is happening after 30 minutes of use but works OK until then it is likely to be either either you missed a clogged filter, or some restriction is causing the fluid to heat up. Is the fluid getting really hot? That would be a clue.

I wish I knew more about the JD closed center type hydraulic system....but I don't. I do know that that closed hydraulic systems for medium size ag tractors tend to be unique to JDs and require some study. It's a field of its own. Luckily there are a lot of really good shop manuals and resources from that era.

Also, if you simply google "John Deere 2020 shudder" you will find that shuddering is a common problem. Lots has been written, and some of it by people who still post on tractor forums.
By the way, the keyword to use for that google search is "shudder"; NOT "shutter".
rScotty

Thanks for the reply, the supply and return hoses are pretty hot into and out of the FEL control valve.

 

[Tx Jim]

Hot hyd lines on hyd system normally indicates a high pressure internal leak. An internal leak on closed center hyd system utilizes a majority of the hyd pumps output which will cause poor hyd performance.

 

[Lanefird]

Hot hyd lines on hyd system normally indicates a high pressure internal leak. An internal leak on closed center hyd system utilizes a majority of the hyd pumps output which will cause poor hyd performance.

Like I said I fixed the leak in the rockshaft valves before this, so no leak or fluid moving I can see there. Where else can I check for leak internally?

 

[Tx Jim]

Power steering,scv,FEL valve or rockshaft are places for internal high pressure leaks.

I'll advise to cap power steering supply line if your tractors serial # is >045,199 & then test loader operation I've forgot if I asked on other forum is your tractors serial # is below or above 045,199

 

[Lanefird]

 

[Lanefird]

 

[Tx Jim]

I had forgotten that your tractor had a hyd "T" fitting in RH side of trans case in lieu of a pressure control(priority) valve. Therefore if your tractor has power steering it will be open center not closed center PS which won't affect FEL hyd operation